According to the U.S. Federal Trade Commission (FTC), in order for a watch to carry the statement “Water Resistant”, it must be able to withstand the static pressure of three atmospheres or about 99 feet under water. This is sufficient to keep the watch dry when hand washing or being caught in a rainstorm. It is not sufficient to protect the watch from the rigors of swimming, because the act of thrusting one’s hand in the water causes a pressure well beyond three atmospheres.
Water resistance is dependent upon perishable rubber gaskets. Soap and hot water have an adverse affect on the gaskets, so one should never shower or enter a hot tub with a watch.
In fact it is our recommendation to never submerse your watch in water. If you are one of those very few people in the world who needs to wear a watch under water, a professional diver, we recommend that you send the watch either to a factory service center or a watchmaker who specializes in servicing divers’ watches and has the necessary equipment to perform high pressure testing.
We have the equipment to test to the three atmosphere specification of the FTC. We will, if asked, and for an additional charge, test your watch for water resistance, and while we will certify the watch as being water-resistant at the time of testing, we will not guarantee it against water damage, because water resistance is a condition that must be maintained on a regular basis, and also because we have no control over the conditions to which the watch may be subjected. Our best advice is do not allow your watch to get wet.